1. Field of the Invention
The present invention relates to X-ray diagnostic systems, and in particular, to such systems for angiographic examinations employing an image intensifier television chain, an image subtraction device connected thereto having two image memories for storing image data taken different times, a device for controlling storage in the image memories, a subtracter for subtracting the memory contents, and a device for displaying the subtraction images.
2. Description of the Prior Art
An X-ray diagnostic system is described in German patent application No. P 31 22 098.3. That system includes a first image memory in which can be stored a single X-ray image, or several integrated X-ray images, obtained prior to subjecting the radiography patient to an injection of an X-ray contrast medium. Such an image is known as a blank image. That system further includes a second image memory in which can be stored a single X-ray image, or several integrated X-ray images, obtained after injecting the patient with the X-ray contrast medium. Such an image is known as a filling image. An image subtraction device subtracts the stored blank image from the stored filling image, thereby producing a difference or subtraction image which shows only the blood vessels important to the diagnosis.